The present invention relates to a semiconductor device and a control system, and particularly to a technique effectively applied to a semiconductor device that is required to have high security.
Devices such as cellular phones, IC cards, automobiles, and industrial machines incorporate microcontrollers. The microcontrollers are semiconductor devices that control the respective devices by performing processing in accordance with programs stored in memories. The microcontrollers are required to have security according to uses. For example, a microcontroller incorporated in an IC card having the function of encrypting and authenticating information is required to have high security in order to prevent the fraudulent use and falsification of data, malfunction, and the like. For example, the microcontroller that is incorporated in the IC card etc. and required to have high security (hereinafter also referred to as a “secure microcontroller”) is required not to malfunction even if attacks to draw security information are performed through various techniques, which is vital to the product. One of such attack techniques is, for example, a laser attack. By the laser attack, the semiconductor device such as the secure microcontroller is locally irradiated with a laser beam, thereby causing a malfunction of an internal circuit including a CPU, a memory, and the like.
For example, Japanese Unexamined Patent Publication No. 2009-253297 (Patent Document 1) discloses a related art for a measure against the laser attack. According to the technique disclosed in Patent Document 1, a protection shield comprised of a doped region (N-well) is provided deep inside a semiconductor substrate so as to form a current path upon laser irradiation, and a current in the current path is detected, thereby detecting the laser attack.
In addition, for example Japanese Unexamined Patent Publication No. 2009-38186 (Patent Document 2) discloses a related art for enhancing the security of the semiconductor device. According to the technique disclosed in Patent Document 2, the operating power supply voltage of an internal circuit is separated from the power supply voltage of an N-well where the internal circuit is formed, and a detection circuit detects an increase in current flowing into the N-well at the time of latchup, thereby detecting the latchup.